Ultrasonically excited comb

Abstract

A comb for hair or fibres is discloses which comprises a rigid comb body having a spine extending along a longitudinal axis and a plurality of teeth projecting from the spine and extending transversely to the longitudinal axis, and at least one ultrasound generator connected to the spine . In the invention, the or each ultrasound generator comprises at least one ultrasonic transducer operative to apply compression waves to the spine in a direction transverse to the longitudinal axis of the spine so as to cause surface waves to propagate along the spine and the teeth of the comb body.

1 . A comb for hair or fibres comprising
 a rigid comb body having a spine extending along a longitudinal axis and a plurality of teeth projecting from the spine and extending transversely to the longitudinal axis; and   at least one ultrasound generator connected to the spine, wherein   the or each ultrasound generator comprises at least one ultrasonic transducer operative to apply compression waves to the spine in a direction transverse to the longitudinal axis of the spine, so as to cause surface waves to propagate along the spine and the teeth of the comb body.   
     
     
         2 . The comb of  claim 1 , wherein the ultrasound generator comprises a plurality of transducers arranged with an equal number of transducers on each side of the spine, the spine being clamped between the ultrasonic transducers. 
     
     
         3 . The comb of  claim 2 , wherein the comb body is made of metal. 
     
     
         4 . The comb of  claim 3 , wherein the comb body serves as an electrical ground plane of the transducers. 
     
     
         5 . The comb of  claim 1 , further comprising a source of a.c. voltage connected to the ultrasonic transducers, the source having an excitation frequency tuned to cause resonance of the ultrasonic vibrations travelling along the teeth of the comb body in at least one mode of propagation. 
     
     
         6 . The comb of  claim 5 , wherein the excitation frequency is selected such that the length of the teeth is an integer multiple of one half of the wavelength of the ultrasonic vibrations induced in the comb body. 
     
     
         7 . The comb of  claim 4 , wherein the teeth of the comb body are separated from one another by a distance that is an integer multiple of one half of the wavelength of the ultrasonic vibrations induced in the comb body. 
     
     
         8 . The comb of  claim 5 , wherein the teeth of the comb body are separated from one another by a distance that is an integer multiple of one half of the wavelength of the ultrasonic vibrations induced in the comb body. 
     
     
         9 . The comb of  claim 1 , wherein the ultrasonic vibrations produced by the ultrasound generator propagate as Lamb waves along the teeth of the comb body. 
     
     
         10 . A hair or fibre treatment apparatus comprising a comb and a dispenser for applying a hair treatment product to be worked into the hair or fibre by the comb, the comb comprising:
 a rigid comb body having a hollow spine extending along a longitudinal axis and a plurality of hollow teeth projecting from the spine and extending transversely to the longitudinal axis, the hair treatment product being able to flow from the dispenser through the hollow spine and teeth to the hair or fibre being treated;   and   at least one ultrasound generator connected to the spine; wherein   the or each ultrasound generator comprises at least one ultrasonic transducer operative to apply compression waves to the spine in a direction transverse to the longitudinal axis of the spine, so as to cause surface waves to propagate along the spine and the teeth of the comb body.   
     
     
         11 . The treatment apparatus of  claim 10 , wherein the ultrasound generator comprises a plurality of transducers arranged with an equal number of transducers on each side of the spine, the spine being clamped between the ultrasonic transducers. 
     
     
         12 . The treatment apparatus of  claim 11  wherein the comb body is made of metal. 
     
     
         13 . The treatment apparatus of  claim 12 , wherein the comb body serves as an electrical ground plane of the transducers. 
     
     
         14 . The treatment apparatus of  claim 13 , further comprising a source of a.c. voltage connected to the ultrasonic transducers, the source having an excitation frequency tuned to cause resonance of the ultrasonic vibrations travelling along the teeth of the comb body in at least one mode of propagation. 
     
     
         15 . The treatment apparatus of  claim 14 , wherein the excitation frequency is selected such that the length of the teeth is an integer multiple of one half of the wavelength of the ultrasonic vibrations induced in the comb body. 
     
     
         16 . The treatment apparatus of  claim 13 , wherein the teeth of the comb body are separated from one another by a distance that is an integer multiple of one half of the wavelength of the ultrasonic vibrations induced in the comb body. 
     
     
         17 . The treatment apparatus of  claim 13 , wherein the teeth of the comb body are separated from one another by a distance that is an integer multiple of one half of the wavelength of the ultrasonic vibrations induced in the comb body. 
     
     
         18 . The treatment apparatus of  claim 10 , wherein the ultrasonic vibrations produced by the ultrasound generator propagate as Lamb waves along the teeth of the comb body. 
     
     
         19 . A method of treating hair or fibre which comprises:
 providing a comb body having a spine extending along a longitudinal axis and a plurality of teeth projecting from the spine and extending transversely to the longitudinal axis,   combing the hair or fibre by means of the comb body, and   transmitting ultrasound along the spine and the teeth of the comb body during the combing;   wherein   the transmitting of ultrasound along the spine and the teeth of the comb body comprises causing surface waves to propagate along the spine and the teeth of the comb body by connecting at least one ultrasonic transducer to apply compression waves to the spine in a direction transverse to the longitudinal axis of the spine.